Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,272	$ (8,125)	$ (19,145)	$ (36,908)
Other comprehensive income (loss):
Foreign currency translation adjustments, net of zero tax	(4,615)	(5,588)	(3,468)	(7,968)
Unrealized gains on available-for-sale securities, net of zero tax	0	0	0	1
Total other comprehensive loss	(4,615)	(5,588)	(3,468)	(7,967)
Comprehensive loss	$ (2,343)	$ (13,713)	$ (22,613)	$ (44,875)